Credit

Caption

Computer illustration of a normal male karyotype, the full complement of male chromosomes arranged in numbered homologous pairs. The chromosomes are presented in this manner by matching up unpaired chromosomes photographed during the metaphase stage of cell division. Each member of a homologous pair is similar in length & banding pattern. Male & female sets differ only in the sex pair (bottom right); a female would be labelled XX instead of XY. The nucleus of each human cell contains a total of 46 chromosomes, 23 of maternal and 23 of paternal origin.